Interactive effects of zinc and copper sources and phytase on growth performance, mineral digestibility, bone mineral concentrations, oxidative status, and gut morphology in nursery pigs

Abstract

<jats:title>Abstract</jats:title> <jats:p>This study investigated the interactive effects of zinc (Zn) and copper (Cu) sources and phytase on growth performance, oxidative status, mineral digestibility, tissue mineral concentrations, and gut morphology in nursery pigs. A total of 288 weaning barrows [body weight (BW) = 5.71 ± 0.81 kg], blocked by initial BW, were randomly allotted to one of eight dietary treatments, with nine pens per treatment and four pigs per pen. The eight dietary treatments were arranged in 2 × 2 × 2 factorial design, with two Zn sources [2,000, 2,000, and 100 mg/kg Zn from zinc oxide (ZnO) during phase 1 (days 1–14) and phase 2 (days 15–28), and phase 3 (days 29–42), respectively; 100 mg/kg Zn from zinc methionine hydroxy analogue chelate (Zn-MHAC) from phases 1 to 3], two Cu sources [150, 80, and 80 mg/kg Cu from copper sulfate (CuSO4) or copper methionine hydroxy analogue chelate (Cu-MHAC) during phases 1–3, respectively], and two phytase inclusion levels (0 or 500 FTU/kg). Results showed that ZnO supplementation at 2,000 mg/kg Zn significantly increased average daily feed intake (ADFI; P = 0.01) and average daily gain (ADG; P = 0.03) during phase 1 compared to Zn-MHAC group; however, Zn-MHAC supplementation tended (P = 0.06) to improve gain to feed ratio (G:F) during phase 2 compared to ZnO group. There were no differences (P &amp;gt; 0.10) between ZnO and Zn-MHAC groups in terms of ADG, ADFI, and G:F during the entire nursery period. Compared with CuSO4, Cu-MHAC tended to increase ADG (P = 0.07) and G:F (P = 0.08) during the entire nursery period. Phytase supplementation significantly increased ADG (P &amp;lt; 0.01), ADFI (P &amp;lt; 0.01), and G:F (P &amp;lt; 0.01) during the entire nursery period compared with no phytase supplementation. There was a significant interaction (P &amp;lt; 0.01) between Zn source and phytase on standardized total tract digestibility (STTD) of phosphorus (P), whereas there was no interaction (P = 0.21) between Cu sources and phytase on STTD of P. However, there was a significant interaction between Cu sources and phytase on calcium (Ca; P = 0.02) and P (P = 0.03) concentrations in metacarpal bones and G:F in phase 2 (P = 0.09). Furthermore, pigs fed diets containing Zn-MHAC tended to have lower ileum villus width (P = 0.07), compared with those fed diets containing ZnO, and pigs fed diets containing Cu-MHAC tended to have lower plasma malondialdehyde concentration (P = 0.10) compared with those fed diets containing CuSO4. In conclusion, under the conditions of the current study, ZnO supplementation at 2,000 mg/kg Zn was only effective in the first 2 wk postweaning, whereas Zn-MHAC supplementation at 100 mg/kg Zn could achieve better feed efficiency during phase 2 compared to pharmacological levels of ZnO, therefore, leading to no difference of growth performance in the entire nursery period. Low levels of Zn-MHAC may improve phytase efficacy on degrading phytate P compared to pharmacological levels of ZnO. Cu-MHAC may be more effective to promote growth compared to CuSO4, which may be partially driven by reduced oxidative stress. Results also indicated that Cu-MHAC might exert a synergistic effect with phytase on improving feed efficiency and bone mineralization.</jats:p>

Zinc Supplementation Forms Influenced Zinc Absorption and Accumulation in Piglets

“…The current study demonstrated that Zn-Met added in feed improved Zn apparent digestibility. This is in agreement with previous studies, in which organic Zn sources such as Zn-Met, Zn-proteinate and Zn-glycinate had a greater bioavailability as compared to inorganic Zn forms [ 23 , 24 , 25 ]. Moreover, this study found that ZnSO 4 dissolved in drinking water also had higher Zn apparent digestibility in comparison with ZnSO 4 added in feed.…”

“…Zn-Met, organic metal chelates composed of Zn chelated with Met in coordinate covalent bonds, chelate is stable in the small intestine, may minimize the formation of Zn-phytate complex and allow more Zn to be absorbed by the epithelial cells in the small intestine [ 22 ]. In contrast, inorganic form, ZnSO 4 , is easily dissociated in the stomach and intestine, therefore, Zn-phytate complex is formed, rendering a lower absorption of Zn [ 23 ]. The current study demonstrated that Zn-Met added in feed improved Zn apparent digestibility.…”

Interactive Effects of Copper Sources and a High Level of Phytase in Phosphorus-Deficient Diets on Growth Performance, Nutrient Digestibility, Tissue Mineral Concentrations, and Plasma Parameters in Nursery Pigs

“…Technology advancement has led to the development of numerous forms of organic Cu, which have been shown to be more bioavailable than CuSO 4 [3]. Studies have demonstrated that Cu-proteinate [5] and Cu-MHAC [6,7,9] achieved greater growth performance in nursery pigs than CuSO 4 at the same Cu inclusion levels, which was further supported by the current study that Cu-MHAC achieved greater average daily gain than CuSO 4 in the presence of phytase supplementation at 1500 FTU/kg. The fact that average daily gain in nursery pigs was not different between Cu-MHAC and CuSO 4 without phytase in the present study indicated that the impact of P deficiency might overshadow the beneficial effect of Cu-MHAC or P deficiency may impair the function and utilization of Cu in the body.…”

“…An in vitro model has demonstrated that Cu lysine is less inhibitive to phytase compared with CuSO 4 [11]. Our recent data also suggests that Cu-MHAC may enhance phytase efficacy on bone mineralization in nursery pigs when 500 FTU/kg phytase is used, compared with CuSO 4 [9]. However, there is no data on the interaction of copper source and phytase supplementation at high levels on growth performance and mineral digestibility in pigs.…”

“…Supplementation of Cu as Cu-citrate (125 mg/kg Cu) or Cu-proteinate (100 mg/kg Cu) has been shown to achieve similar growth performance in nursery pigs as CuSO 4 supplementation at 250 mg/kg Cu [4,5]. Similarly, supplementation of copper methionine hydroxy analogue chelate achieved greater average daily gain and feed efficiency in nursery or grow-finish pigs compared with pigs fed CuSO 4 or tribasic copper chloride at equivalent Cu levels [6][7][8][9].…”